I'll be honest I had to look this up....never heard the term "heiferette". http://en.wiktionary.org/wiki/heiferette
Noun: heiferette (plural heiferettes)
1.A female bovine, usually more than six months of age and less than two years of age, that has had no more than one calf.
Noun: heifer (plural heifers)
1.A young female bovine (cow) that has not yet had a calf.
Noun: Cow cow (plural cows, cattle or kine (archaic))
1.A female domesticated ox or other bovine, especially an adult after she has had a calf.
2.More generally, any domestic bovine regardless of sex or age.
3.The meat (beef) of such animals, used as food for humans.
4.The female of larger species of mammal, including bovines, moose, whales, seals, hippos, rhinos, manatees, and elephants.
5.(UK, derogatory, informal) A woman who is considered despicable in some way, especially one considered to be fat, lazy, ugly, argumentative, mean or spiteful.
6.(informal) Anything that is annoyingly difficult, awkward or graceless.
That website is a real cow to navigate.
7.(informal) A conniption fit or hissy fit; a state of agitation (only in the phrase have a cow).
I learned something new today! That being said... I'm not about to start using the word. In my neck of the woods a heifer has had no calf and as soon as she does she's a cow! Which per the definitions is completely right and acceptable!
IMO alot of the english language is regional doesn't make anyone more right or wrong just means you live in different areas!